Wearable air bag systems are known for vehicles, particularly for two-wheeled motor vehicles. See, for example, Japanese Unexamined Patent Publication No. Hei 9-66789. In such a wearable air bag system, a rider wears a clothing article provided with an air bag module including an air bag body and an inflator. When a two-wheeled motor vehicle has had a collision, the inflator is actuated, and the air bag is expanded and deployed to cushion an impact on the rider.
In a known wearable air bag system, an air bag body provided on a clothing article worn by a rider includes a bag-shaped member and becomes an expanded elastic body by containing high-pressure gas generated by an inflator. The air bag body is formed by only a bag-shaped member. Accordingly, when a two-wheeled motor vehicle is subjected to an excessive impact force of some prominence that collides against the air bag, an excessive load locally and intensively acts on the air bag body. This may affect a function of the air bag body which cushions an impact on the rider.